14,633 research outputs found

    Experimental realization of the Yang-Baxter Equation via NMR interferometry

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    The Yang-Baxter equation is an important tool in theoretical physics, with many applications in different domains that span from condensed matter to string theory. Recently, the interest on the equation has increased due to its connection to quantum information processing. It has been shown that the Yang-Baxter equation is closely related to quantum entanglement and quantum computation. Therefore, owing to the broad relevance of this equation, besides theoretical studies, it also became significant to pursue its experimental implementation. Here, we show an experimental realization of the Yang-Baxter equation and verify its validity through a Nuclear Magnetic Resonance (NMR) interferometric setup. Our experiment was performed on a liquid state Iodotrifluoroethylene sample which contains molecules with three qubits. We use Controlled-transfer gates that allow us to build a pseudo-pure state from which we are able to apply a quantum information protocol that implements the Yang-Baxter equation.Comment: 10 pages and 6 figure

    Remote Sensing techniques used to characterize soil erosion in southwestern Sao Paulo state

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    Within randomly sampled squares of a 1 km x 1 km grid, rill/gullies frequency, land cover/land use type and shape of the slopes were extracted from aerial photographs of the Ribeirao Anhumas drainage basin. Mean slope gradient, stream frequency and slope length were calculated on topographic maps. Ground truth data on fine sand/coarse sand ratio and vegetation cover densities were obtained. The MSS-LANDSAT-2 data (CCTs) were analyzed using single-cell, cluster synthesis and slicer algorithms. Graphical and statistical analyses of the data indicate that different slope gradients and land cover/land use types are the most significant factors related to the soil erosion process. The digital analysis of MSS data allowed the association among gray level classes and vegetation cover classes, which defined seven classes. These gray level classes and slope gradient classes were used to rank erosion risk

    Quantum Cosmology in Scalar-Tensor Theories With Non Minimal Coupling

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    Quantization in the minisuperspace of non minimal scalar-tensor theories leads to a partial differential equation which is non separable. Through a conformal transformation we can recast the Wheeler-DeWitt equation in an integrable form, which corresponds to the minimal coupling case, whose general solution is known. Performing the inverse conformal transformation in the solution so found, we can construct the corresponding one in the original frame. This procedure can also be employed with the bohmian trajectories. In this way, we can study the classical limit of some solutions of this quantum model. While the classical limit of these solutions occurs for small scale factors in the Einstein's frame, it happens for small values of the scalar field non minimally coupled to gravity in the Jordan's frame, which includes large scale factors.Comment: latex, 18 page

    Observation of environment-induced double sudden transitions in geometric quantum correlations

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    Correlations in quantum systems exhibit a rich phenomenology under the effect of various sources of noise. We investigate theoretically and experimentally the dynamics of quantum correlations and their classical counterparts in two nuclear magnetic resonance setups, as measured by geometric quantifiers based on trace-norm. We consider two-qubit systems prepared in Bell diagonal states, and perform the experiments in decohering environments resulting from Bell diagonal-preserving Markovian local noise. We then report the first observation of environment-induced double sudden transitions in the geometric quantum correlations, a genuinely nonclassical effect not observable in classical correlations. The evolution of classical correlations in our physical implementation reveals in turn the finite-time relaxation to a pointer basis under nondissipative decoherence, which we characterize geometrically in full analogy with predictions based on entropic measures.Comment: 5 pages, 2 figures. v2: Minor corrections. Published versio

    Aplikasi Rajutan Bambu Sebagai Tulangan Balok Beton

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    Need for the use of reinforced concrete in housing construction will increase along with the rapid population growth. This increases the need for steel reinforcement as a major component. The increase in need for steel reinforcement will trigger a price increase so that it becomes expensive and scarce. Iron ore as a raw material for making steel reinforcement is a mineral that can not be renewed. Therefore, efforts to use alternatives to steel reinforcement in concrete. Bamboo has good mechanical properties and a high ratio between strength and weight. Bamboo has a tensile strength is high, between 100-400 MPa, nearly matching the tensile strength equivalent to steel reinforcement ½ to ¼ of iron ultimate voltage (Widjaja, 2001) and (Surjokusumo and Nugroho, 1993) showed similar results and by the Moriscos, 1996 that the tensile strength of bamboo can reach 1280 kg / cm2. Bamboo can be used as the material of reinforced concrete. This study aims to determine the capacity of the bending beam with reinforcement of bamboo, bamboo reinforced beam deflection capacity. This experiment is a concrete beam bending test. The results showed that bamboo reinforced concrete beam has a maximum capacity reached 56.61% of the maximum capacity of steel reinforced concrete

    Experimental and modeling studies of a micro direct methanol fuel cell

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    The Direct Methanol Fuel Cell (DMFC) has attracted much attention due to its potential applications as a power source for transportation and portable electronic devices. Based on the advantages of the scaling laws, miniaturization promises higher efficiency and performance of power generating devices and the MicroDMFC is therefore an emergent technology. In this work, a set of experiences with a MicroDMFC of 2.25 cm2 active area are performed in order to investigate the effect of important operating parameters. Maximum power density achieved was 32.6 mW/cm2 using 4M mehanol concentration at room temperature. Polarization curves are compared with mathematical model simulations in order to achieve a better understanding of how parameters affect performance. The one-dimensional model used in this work takes in account coupled heat and mass transfer, along with the electrochemical reactions occurring in a direct methanol fuel cell and was already developed and validated for DMFC in previous work [1-3]. The model is also used to predict some important parameters to analyze fuel cell performance, such as water transport coefficient and methanol crossover. This easy to implement simplified model is suitable for use in real-time MicroDMFC simulations

    Efficient Enzymatic Preparation of Flavor Esters in Water

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    A straightforward biocatalytic method for the enzymatic preparation of different flavor esters starting from primary alcohols (e.g., isoamyl, n-hexyl, geranyl, cinnamyl, 2-phenethyl, and benzyl alcohols) and naturally available ethyl esters (e.g., formate, acetate, propionate, and butyrate) was developed. The biotransformations are catalyzed by an acyltransferase from Mycobacterium smegmatis (MsAcT) and proceeded with excellent yields (80-97%) and short reaction times (30-120 min), even when high substrate concentrations (up to 0.5 M) were used. This enzymatic strategy represents an efficient alternative to the application of lipases in organic solvents and a significant improvement compared with already known methods in terms of reduced use of organic solvents, paving the way to sustainable and efficient preparation of natural flavoring agents

    Principais doenças da cultura do milho.

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    Nos últimos anos, tem-se presenciado o aumento da incidência de doenças na cultura do milho, que resulta em quedas na produtividade e na qualidade dos grãos. As causas do aumento da incidência dessas doenças são a monocultura do milho, as alterações climáticas e o manejo cultural adotado, fazendo com que os patógenos (fungos, bactérias, nematóides, vírus, molicuttes) permaneçam por mais tempo na área de cultivo. O manejo de doenças do milho exige o empenho do produtor, que resultará numa maior ou menor eficiência do controle. Estão disponíveis no mercado, híbridos que apresentam diferentes graus de resistência para diferentes doenças, mas não para todas. Para algumas doenças foliares, causadas por fungos, há trabalhos comprovando a viabilidade e a eficiência do controle químico, podendo assim fazer parte do sistema de manejo da cultura
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